This invention generally relates to a digital communication network and apparatus and method for expanding such networks without disruption of service.
The architecture of known digital communication networks restrict unlimited channel expansion in daisy chain fashion and do not allow expansion of the network to an unlimited number of channels while maintaining a nonblocking condition.
Specifically, in known large networks, as the number of channels increases, the probability of blocking also increases. Blocking occurs whenever a node of the system is prevented from communicating with any other node of the system, or itself, which is not busy. This expansion problem results because the timing in other networks is fixed while the addition of space stages causes the addition of time delays.
Another problem with known networks is that they require more than two different printed circuit boards, or modules, in order to implement the network and any expansion elements.
Another disadvantage of known digital networks is that they do not readily provide for on line expansion.